USGS Topographic Maps

Update 11/28/2011 Seamless Topo Maps - I have released a seamless version (without the map borders) version of the USGS Topographic Map layer for Google Earth. In addition to removing the map borders, hill shading has been added using the 10-meter National Elevation Dataset (NED), which greatly enhances the topography and makes it possible to “see” the 3D effects when using Google Earth in off-line mode. Given the amount of time required to create this layer, and the server resources required, I will be charging a small fee to download the seamless maps. Making the maps available for download allows me to make them available at a higher resolution than I would be able to otherwise. See the Seamless Topographic Maps for Google Earth page for more information. A couple of screenshots are below.

USGS Topographic maps provide detailed information such as land use, feature names, the locations of natural features, and topographic elevation contours. There are over 50,000 7.5-minute topo maps covering the entire United States (except Alaska, which is covered in a larger scale). The topographic maps come in a variety of scales, with the most detailed typically being the 7.5-minute version, meaning each map covers an area of 0.125 x 0.125 degrees. This collection of maps lets you easily view all 50,000+ of the 7.5-minute USGS topographic maps in Google Earth.

The maps in this collection typically date from around 1978 to 2005. The USGS is constantly updating the topographic maps and it seems to take them about 15 to 20 years to get around to updating each individual map. I also have a separate collection of Historic USGS Topographic maps for Google Earth.

Each topographic map has been converted to a single Google Earth KMZ file, which is typically about 1-5 megabytes. The maps include the collars (borders), which have information such as the date of the map and the source of the data found on the map.

The topo maps are accessed by a very simple index. Just zoom in until the blue and green outlines become visible. Then click on the box for the Topographic map you wish to view to bring up the balloon with some information about the map and a View Map button. Click on the View Map button and after a few seconds (where it will look like nothing is happening), the map will appear in Google Earth.

Once the map loads, you can use the use the topo maps with the many other features included with Google Earth, such as:

Import and overlay GPS Tracks

Adjust the transparency of the topo maps

View Google Earth’s 3D buildings on top of the topo maps

Output to your printer

Compare features on the topo maps to the Google Earth imagery

The speed at which the maps load will depend on the speed of your Internet connection and the speed of my web host. When the map is loading, it may look like nothing is happening for a few seconds. But if your on a reasonably fast Internet connection, the map should appear after about 10-60 seconds.

To get started, first make sure you have Google Earth installed. Then just click on the button below to load the KML file into the Places folder of Google Earth.

Embed Maps In Website

The Topographic Maps can easily be embedded into your own website using the Google Earth Plugin. The first step in this process is to determine the URL of the map you are interested in. To determine the URL, find the map you want to embed and write down the map code found in the pop up balloon. For this example, we will use o37122g4, which is San Francisco North California. The URL of your map can be determined by replacing the o37122g4 map code with your map code in the URL below.

http://www.topomaparchive.com/maps/Topos_Current/37122/o37122g4.kmz

Next, go to www.takitwithme.com and paste the URL for your map into the box at the top of the page (give it time to load it). Click a couple buttons and you’ll have your embed code, which can be put on your web site with results similar to below.